15067-04-6Relevant academic research and scientific papers
Method for preparing halogenated sugar under mild conditions
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Paragraph 0040-0042, (2020/07/02)
The invention discloses a method for preparing halogenated sugar under mild conditions. The method comprises the following steps that an easily-prepared thioglycoside donor and a halogen simple substance or halogen intercompound undergo a reaction at room temperature to obtain the halogenated sugar (chlorine, bromine and iodine). The halogen simple substance or the halogen intercompound is commercial easily available iodine elementary substance, iodine bromide and iodine chloride. The method is suitable for various pyranoses and furanoses. The method has no limitation on a protecting group ofthe thioglycoside donor, and the protecting group can be an electron withdrawing group such as acetyl, benzoyl and the like, and can also be an electron donating group such as benzyl, silicon base andthe like. Meanwhile, the reaction can occur in various organic solvents such as dichloromethane, acetonitrile and methylbenzene. The preparation method of the halogenated sugar is simple, reaction conditions are mild, raw materials are easy to obtain, the application range is wide, the halogenated sugar is compatible with acid-labile groups such as isopropylidene ketal and silicon groups, and a pure product can be obtained by removing a solvent from the halogenated sugar which is not stable in the separation process.
Synthesis of glycosyl chlorides using catalytic Appel conditions
Pongener, Imlirenla,Nikitin, Kirill,McGarrigle, Eoghan M.
supporting information, p. 7531 - 7535 (2019/08/20)
The stereoselective synthesis of glycosyl chlorides using catalytic Appel conditions is described. Good yields of α-glycosyl chlorides were obtained using a range of glycosyl hemiacetals, oxalyl chloride and 5 mol% Ph3PO. For 2-deoxysugars treatment of the corresponding hemiacetals with oxalyl chloride without phosphine oxide catalyst also gave good yields of glycosyl chloride. The method is operationaly simple and the 5 mol% phosphine oxide by-product can be removed easily. Alternatively a one-pot, multi-catalyst glycosylation can be carried out to transform the glycosyl hemiacetal directly to a glycoside.
Efficient Synthesis of α-Glycosyl Chlorides Using 2-Chloro-1,3-dimethylimidazolinium Chloride: A Convenient Protocol for Quick One-Pot Glycosylation
Tatina, Madhu Babu,Khong, Duc Thinh,Judeh, Zaher M. A.
supporting information, p. 2208 - 2213 (2018/06/04)
A mild and convenient method for the synthesis of α-glycosyl chlorides in high 80–96 % yields within 15–30 min using 2-chloro-1,3-dimethylimidazolinium chloride (DMC) is disclosed. The method has a wide substrate scope and is compatible with labile OH protecting groups, including benzyl, acetyl, benzoyl, isopropylidene, benzylidene, TBDMS (tert-butyldimethylsilyl), and TBDPS (tert-butyldiphenylsilyl) groups. The excellent α selectivity obtained in this reaction is attributed to in-situ isomerization of β-glycosyl chlorides to the more stable α-glycosyl chlorides, as demonstrated by 1H NMR spectroscopic studies. Disarmed sugars with OBz or OAc groups at C-2 were chlorinated at a faster rate but ismomerized (β→α) at a slower rate than armed sugars with an OBn group at C-2. More importantly, the method enables highly desirable one-pot glycosylation reactions to take place, thus allowing efficient syntheses of disaccharides and simple O-glycosylated sugars in high overall yields without the need for separation or purification of the α-glycosyl chloride donors. This method will be especially useful for direct glycosylation reactions using glycosyl chloride donors that are unstable upon separation and purification.
METHOD FOR PRODUCING a-HALO-TETRAACYL-GLUCOSE
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, (2016/01/29)
There is provided an efficient and excellent preparation method of an α-halo-tetraacyl-glucose which is suitable for industrial preparation, which comprises reacting D-glucose or lower alkyl D-glucoside with a reactive derivative of a carboxylic acid and a metal halide to prepare the α-halo-tetraacyl-glucose represented by the formula (III): wherein R represents an optionally substituted lower alkyl group or an optionally substituted aryl group, and X represents a halogen atom, in one step, and the resulting α-halo-tetraacyl-glucose (III) can be converted into a compound of the formula (I) or a salt thereof by subjecting to a conventional method.
Indium(III) triflate-mediated one-step preparation of glycosyl halides from free sugars
Giri, Santosh Kumar,Kartha, K. P. Ravindranathan
experimental part, p. 3378 - 3383 (2010/12/25)
In(OTf)3 has been found to be an efficient catalyst for the direct conversion of reducing sugars to their respective acylated glycosyl halides in good yields under mild conditions. The glycosyl halides so obtained can be converted to alkyl glyc
Stereoselective glycosylations using benzoylated glucosyl halides with inexpensive promoters
Murakami, Teiichi,Sato, Yukari,Shibakami, Motonari
, p. 1297 - 1308 (2008/09/21)
Reactions of O-benzoylated glucopyranosyl halide (I, Br), isolated or generated in situ from per-benzoylated glucose (8a) and trimethylsilyl halide, with various alcohols were efficiently promoted by zinc halide (Cl, Br) or N-bromosuccinimide with a catal
Highly stereoselective synthesis of peracylated α-aldopyranosyl chlorides from aldopyranose peracetates and thionyl chloride catalyzed by BiCl3 generated in situ from the procatalyst BiOCl
Ghosh, Rina,Chakraborty, Arijit,Maiti, Swarupananda
, p. 9631 - 9634 (2007/10/03)
Aldopyranose peracetates react with thionyl chloride and BiCl3, generated in situ from a substoichiometric amount of the procatalyst BiOCl, producing the corresponding peracylated aldopyranosyl chlorides in very good to excellent yields (82-97%
